Fluid end

ABSTRACT

A fluid end for a high-pressure pump including a metallic block having a front, back, top, bottom, and opposed sides. The block has a horizontal, plunger passage extending from the front to the back thereof. A horizontal, outlet passage extends from one of the opposed sides of the block to the other with the outlet passage being positioned beneath, and at right angles to, the plunger passage. A suction passage extends vertically downward from the top of the block and intersects the plunger passage to define a pumping chamber at the point of intersection. A discharge passage extends vertically downward from the pumping chamber to the bottom of the block. The discharge passage is located adjacent to the outlet passage. A connector passage extends from the discharge passage to the outlet passage so as to place the discharge passage and outlet passage in fluid communication. A reciprocating plunger assembly is located the end of the plunger passage adjacent the back of the block. A plug is located in the end of the plunger passage adjacent the front of the block. A suction valve is located in the suction passage. A discharge valve is located in the discharge passage. A fluid supply manifold is pivotally secured to the top of the block and is in fluid communication with the suction passage.

FIELD OF THE INVENTION

The present invention relates generally to pumps having pumping chamber pressure responsive fluid distributors.

BACKGROUND OF THE INVENTION

It is difficult to economically produce hydrocarbons from low permeability reservoir rocks. Oil and gas production rates are often boosted by hydraulic fracturing, a technique that increases rock permeability by opening channels through which hydrocarbons can flow to recovery wells. During hydraulic fracturing, a fluid is pumped into a reservoir rock under high pressure where it cracks or fractures the rock. Proppants are carried in suspension by the pumped fluid into the fractures. When the pressure is released, the fractures close on the proppants leaving open channels for hydrocarbons to flow.

Specialized pumps are used to deliver fracture fluids at sufficiently high rates and pressures to complete a hydraulic fracturing procedure or “frac job.” These pumps are usually provided with fluid ends having both reciprocating plungers that place fluids under pressure and valves that control the flow of fluids to and from the plungers. Fluid ends have many parts that are releasably fastened to one another so that the plungers and valves can be easily repaired or replaced. It is the connections between the parts and the supporting features for the valves that tend to weaken a fluid end, limiting its pressure rating, and making it susceptible to cracking under high, cyclical stresses. Thus, fluid ends sometimes fail prematurely.

In an effort to increase pressure ratings and decrease failure rates, improved fluid ends have been proposed by pump manufacturers. One of the principal improvements involves increasing the angles at which the principal flow channels meet so as to reduce internal stresses. The resulting, Y-type fluid ends are costly to make, however. A continuing need, therefore, exists for a strong and lower priced alternative that delivers fracture fluids to reservoir rocks at very high rates and pressures.

SUMMARY OF THE INVENTION

In light of the problems associated with the known fluid ends associated with high-pressure pumps, it is a principal object of the present invention to provide a fluid end of great strength, durability, and fatigue resistance. This fluid end features a body made from a single piece of metal with internal flow passages that intersect one another at right angles. One passage within the body contains a reciprocating plunger assembly that pressurizes fluids and others retain valves that control the flow of fluids past the plunger assembly. Since the body does not have joints between subparts, it is not susceptible to corrosion, fluid leaks, and fatigue wear along such joints.

It is another object of the invention to provide a fluid end of the type described with a suction valve positioned above a discharge valve so that fluid flow through the fluid end is generally downward. The hydrostatic head of the pumped fluid in the fluid end minimizes the likelihood of cavitation as the plunger reciprocates and causes the fluid end to operate with little vibration. Further, positioning the discharge valve in a subordinate location permits the pump to be cleared of fluid with a few strokes of the plunger and avoids the risk of cracking the body of the fluid end should the pumped fluid freeze in cold weather.

It is an additional object of the invention to provide a fluid end that features an access port for gaining access to the inner end of the plunger and providing passage for the suction valve seat during assembly or servicing of the fluid end. A two-part plug having an inner, access pin and an outer, retaining nut closes the access port. The access pin is provided with a concavity at its inner end for receiving therein the inner end of the plunger when the plunger reaches its innermost point of travel into the body of the fluid end.

It is a further object of the invention to provide a fluid end featuring a hinge for the attachment of a suction manifold. The hinge permits access to the interior of the fluid end and retains the manifold in a position for ready reattachment. Reattachment is made by means of VICTAULIC clamps.

It is an object of the invention to provide improved features and arrangements thereof in a fluid end for the purposes described which is relatively inexpensive to manufacture and fully dependable in use.

The foregoing and other objects, features, and. advantages of my fluid end will become readily apparent upon further review of the following detailed description of the preferred embodiment as illustrated in the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention may be more readily described with reference to the accompanying drawings, in which:

FIG. 1 is a schematic view showing the relative positions of the three drawing sheets carrying FIGS. 2A, 2B, and 2C.

FIG. 2A is an enlarged, cross-sectional view of the top portion of my fluid end.

FIG. 2B is an enlarged, cross-sectional view of the middle portion of my fluid end.

FIG. 2C is an enlarged, cross-sectional view of the bottom portion of my fluid end.

Similar reference characters denote corresponding features consistently throughout the accompanying drawings.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to the FIGS., the body 10 of my fluid end 12 is shown. Body 10 has a horizontal, plunger passage 14 that extends from its front to its back. Body 10 also has a horizontal, outlet passage 16 that extends from one of its sides to the other and that is positioned beneath, and oriented at right angles to, plunger passage 14. A suction passage 18 extends vertically downward from the top of body 10 to intersect plunger passage 14 and to define a pumping chamber 20 at the point of intersection. A discharge passage 22 extends vertically downward from pumping chamber 20 to the bottom of body 10 and past outlet passage 16. A horizontal, connector passage 24 places discharge passage 22 and outlet passage 16 in fluid communication with one another.

Body 10 is a metallic block, a machined forging. To lower its weight and increase its strength, body 10 is provided with a plunger section 26 of reduced height that contains the outer end of plunger passage 14 and is adapted for attachment to the power end of a high-pressure pump by a plurality of stay rods (not shown). A suction section 28, containing suction passage 18, is integrally formed with plunger section 26 and extends forwardly and upwardly from plunger section 26. Likewise, a discharge section 30, containing discharge passage 22, outlet passage 16 and connector passage 24, is integrally formed with plunger section 26 and suction section 28 and extends forwardly and downwardly from plunger section 26. Suction section 28 and discharge section 30 both taper from their inner ends to their outer ends.

Plunger passage 14 is provided along a first centerline A extending through body 10. At its back end, plunger passage 14 is increased in diameter and is helically threaded at 32 to receive a compressible, packing unit 34 and a correspondingly helically threaded, gland nut 36 that provide a fluid-tight seal around a plunger assembly 38 that reciprocates in plunger passage 14. At its front end, plunger passage 14 is similarly increased in diameter and is helically threaded at 40 to receive a correspondingly helically threaded plug 42. A plug deck or shoulder 44 is formed at the inner end of threaded portion 40 that serves as a stop to prevent the continued inward movement of plug 42 into plunger passage 14.

A small-diameter, lubricating port 46 extends vertically downward from the top of body 10 to intersect the back end of plunger passage 14. More particularly, lubricating port 46 passes through plunger section 26 and connects with plunger passage 14 at the inner end of threads 32. In use, port 46 permits lubricating oil to flow to plunger assembly 38 at a point between packing unit 34 and gland nut 36.

Suction passage 18 has a second centerline B that is coplanar with centerline A and intersects centerline A at a reference point Z in pumping chamber 20 at right angles. Suction passage 18 extends from the top to the bottom of suction section 28. Suction passage 18 has a narrowed, middle part 18 a near its midpoint that connects a helically threaded, top part 18 b to a smooth-walled, bottom part 18 c. The bottom of middle part 18 a defines a suction valve seat deck 48. The top of middle part 18 a is a terraced surface that defines a suction valve retainer deck 50 and a somewhat smaller diameter, suction valve guide deck 51. The innermost portions of decks 48 and 50, located closest to centerline B, are oriented at right angles to centerline B to reduce the likelihood of fatigue-induced cracks forming in body 10 at these locations. Thus, the top surface of seat deck 48 is horizontal.

Discharge passage 22 is centered on centerline B below suction passage 18 and intersects plunger passage 14 at right angles. Discharge passage 22 has a tapered, top part 22 a of generally small diameter, and a middle part 22 b of a somewhat greater diameter, and a helically threaded, bottom part 22 c of even greater diameter. The bottom of part 22 a forms a discharge valve seat deck 52. Similarly, the bottom of part 22 b forms a discharge valve guide deck 54. The innermost portions of decks 52 and 54, located closest to centerline B, are oriented at right angles to centerline B to reduce the likelihood of fatigue-induced cracks forming in body 10 at these locations. The top surface of seat deck 52 is, thus, horizontal.

Reference point Z is placed on centerline A at a location that facilitates the movement of fluid from suction passage 18 through pumping chamber 20 and into discharge passage 22 while plunger assembly 38 reciprocates from its innermost point of travel (its solid-line position to the right of point Z in FIGS. 2A and 2B) where it penetrates plug 42 to its outermost point of travel to the left of point Z. The crossing of centerlines A and B at right angles reduces stresses within body 10 during use and reduces the likelihood of body 10 cracking.

Outlet passage 16 extends across discharge section 30. Connector passage 24 intersects outlet passage 16 at right angles to place discharge passage 22 in fluid communication with outlet passage 16. To either end of discharge section 30 can be connected one or more conduits (not shown) to carry pressurized fluid away from outlet passage 16 and fluid end 12. This pressurized fluid is used, in a typical operation, to fracture subterranean rock formations. Placing outlet passage 16 away from a discharge valve 56 in discharge passage 22 limits the transverse flow of fluid over the discharge valve 56, especially in triplex and quintuplex pumps where three or five sets of passages, plungers and valves are provided in a given fluid end. Discharge valve 56, therefore, runs without interruption or interference from jets of pumped fluids flowing through outlet passage 16 resulting in a smoother-running and more efficient fluid end 12.

Supply manifold 58 delivers fluid to fluid end 12 through suction passage 18. Manifold 58 includes a tubular body 60 whose opposite ends are connected to a fluid source when fluid end 12 is operated. A tubular connector 62 extends downwardly from tubular body 60 to engage the open top of valve retainer 64 of a suction valve 66 positioned in suction passage 18. The bottom of connector 62 is provided with a peripheral slot 68 and the top of valve retainer 64 is provided with a similar, peripheral slot 70. Slots 68 and 70 accommodate a VICTAULIC coupling body 72 of well-known construction for the quick and easy connection of manifold 58 to valve retainer 64. Within body 72 is positioned a VICTAULIC rubber seal 74 to prevent fluid leaks from coupling body 72.

To permit the easy servicing of suction valve 66, one or more hinges 76 join manifold 58 to pump body 10. Each hinge 76 has a mounting bracket 78 secured by one or more threaded fasteners (not shown) to body 10. The inner end of a swing arm 80 is pivotally attached by hinge pin 82 to mounting bracket 78. The outer end of swing arm 80 is affixed to tubular body 60. When VICTAULIC coupling body 72 is removed from fluid end 12, manifold 58 is free to pivot 90° on hinges 76 to the broken line position seen in FIG. -.

Suction valve 66 includes tubular features that permit the passage of fluids and support the action of other features. For example, valve 66 has a valve seat 84 that, during its installation in body 10, is moved through pumping chamber 20 and pressed into the bottom part 18 c of suction passage 18 against seat deck 48. A suction valve guide 86 is located immediately above valve seat 84 and, during its installation in body 10, is moved downwardly through suction passage 18 and engaged with guide deck 51. An externally helically threaded, suction valve retainer 88 is screwed downwardly into the threaded, top part 18 b of suction passage 18 until engaged with retainer deck 50. Valve retainer 88 has a tapered inner passageway 90 with a small-diameter, orifice portion 92 that serves to maintain a fluid velocity through fluid end 12 that is sized to prevent a proppant from dropping out of suspension from a pumped fluid in a manner that might clog suction valve 66. Neither seat 84, nor guide 86, nor retainer 88 moves during the normal operation of fluid end 12.

Suction valve 66 has moving features that act in concert with seat 84, guide 86, and retainer 88. A piston 92 reciprocates within seat 84 and has a head 94 that engages seat 84 to control the flow of fluid through suction passage 18. Piston 92 also has and a stem 96 that extends upwardly from head 94 through guide 86. A valve keeper 98 is fitted upon the top of stem 96 and is retained there by a split ring 100. A compressed spring 102 is positioned between guide 86 and keeper 98 for normally retaining head 94 in engagement with seat 84. Only when the fluid pressure in suction passage 18 is higher than that in pumping chamber 20 will piston 92 move against force of spring 102 to allow fluid to move through suction passage 18 into pumping chamber 20.

Discharge valve 56 is described fully in my co-pending patent application, Ser. No. 12/453,452, filed in the U.S. Patent and Trademark Office on May 12, 2009, and incorporated for all purposes herein. Discharge valve 56 includes valve seat 104 positioned in top part 22 a of discharge passage 22 and a reciprocating piston 106 for controlling the flow of fluid through passage 22. Piston 106 has a head 108 for engaging valve seat 104 and a hollow, tubular, stem 110 extending downwardly from head 108. A discharge valve guide 112 is positioned below piston 106 in passage 22 and has a guide rod 114 that projects upwardly into a socket 116 provided in stem 110 where it is slidably received. A number of radial apertures 118 penetrate the bottom of stem 110 to equalize pressures between passage 22 and socket 116. A compressed spring 120 is disposed between the valve guide 112 and head 108 to normally press head 108 into engagement with seat 104. A discharge valve retainer 122 is screwed into the bottom part 22 c of passage 22 to retain valve 56 within body 10. When plunger assembly 38 is reciprocated to pressurize fluid in pumping chamber 20, that fluid flows through seat 104, past head 108, and onward through discharge passage 22. From discharge passage 22, the pressurized fluid passes through connector passage 24 into outlet passage 16.

Plunger assembly 38 is fully described in my co-pending patent application, Ser. No. 12/588,269, filed in the U.S. Patent and Trademark Office on Oct. 9, 2009, and incorporated for all purposes herein. Plunger assembly 38 includes: a pony rod adapter 124, plunger 126 releasably attached to pony rod adapter 124, and a pony rod (not shown) releasably attached to pony rod adapter 124. Pony rod adapter 124 has a first cylindrical body 128 and a number of apertures 130 penetrating first cylindrical body 128. A first helically threaded pin 132 is affixed to first cylindrical body 128 and projects from one of its ends. A second helically threaded pin 134 is affixed to first cylindrical body 128 and projects from the other of its ends. Plunger 126 has a second cylindrical body 136 for reciprocating within plunger passage 14. Second cylindrical body 136 has a first outer end with a first helically threaded bore 138 for threadably receiving first helically threaded pin 132. Second cylindrical body 136 also has a first inner end with a polygonal socket 140 for receiving a plunger key (not shown) that can be used to unscrew plunger 126 from pony rod adaptor 124 or turn plunger 126 to aid in its removal from the outer end of plunger passage 14.

The front end of plunger passage 14 provides a port in body 10 for gaining access to pumping chamber 20. This access is necessary for inserting an elongated key (not shown) into socket 140 in plunger 126 for rotating and pushing plunger 126 in the event that repair or replacement of plunger 126 is needed. Access is also necessary to install or remove suction valve seat 84 and piston 92; so, the front end of plunger passage 14 is sized to permit the movement of valve seat 84 and piston 92 through it.

Two-part plug 42 normally closes the front end of plunger passage 14. Plug 42 includes an access pin 142 and a retaining nut 144. Access pin 142 has a rod portion 146 that is sized to slide snugly past plug deck 44 and a peripheral flange portion 148 located at the front end of rod portion 146 that is configured to abut plug deck 44. Rod portion 146 has three, peripheral channels 150 that receive O-ring seals 152 therein to prevent pumped fluids from leaking around rod portion 146. The front end of rod portion 146 is provided with a concavity 154 for reducing the weight thereof. A helically threaded bore 156 is provided in rod portion 146 at the center of concavity 154 for receiving a threaded tool (not shown) for grasping and pulling pin 142 from passage 14. The back end of rod portion 146 is provided with another concavity 158 that receives the convex inner end of plunger 126 when plunger 126 is moved to its deepest point in plunger passage 14 when reciprocated.

When screwed into threaded, outer portion 40, nut 144 presses pin 142, and consequently rod portion 146, inwardly with flange 148 tightly engaging a plug deck 44. Nut 144 has an externally, helically threaded body 160 that is screwed into threaded portion 40 and a hexagonal stem 162 that projects outwardly from threaded body 160 that permits nut 144 to be turned by a wrench. A concavity 164 is provided in the back end of threaded body 160 for reducing the weight of body 160.

It is believed that a person having a basic knowledge of high-pressure pumps would have no trouble making and using fluid end 12. Fluid end 12 pressurizes fluids by the reciprocating action of plunger assembly 18 that draws fluids from suction manifold 58, through valve 66, into pumping chamber 20. From pumping chamber 20 the continuous reciprocation of plunger assembly 18 forces the fluids into discharge passage 22, through discharge valve 56, and finally through passages 24 and 16. Valves 66 and 56 keep fluid moving in a downward direction, working with gravity, through fluid end 12, flushing proppants and minimizing the likelihood of cavitation. Fluid leaving fluid end 12 through outlet passage 16 can be used, in an oilfield environment, to fracture subterranean rocks.

Maintaining fluid end 12 is easy. Access to suction valve 66 for servicing is accomplished by removing plug 42 from plunger passage 14 and moving power end so that plunger 126 is withdrawn from pumping chamber 20. Access to discharge valve 56 is, likewise, accomplished by unscrewing retainer 122 from discharge passage 22 and pulling the remainder of its components. The replacement of body 10 is rare since its configuration inhibits the development of internal, stress fractures. The useful life of fluid end 12 is, therefore, believed to be greater than that comparable fluid ends now in use.

While fluid end 12 has been described with a high degree of particularity, it will be appreciated by some that modifications can be made to it. For example, the number and location of passages 14, 16, 18, 22 and 24 as well as the features associated therewith can be varied. Therefore, it is to be understood that my invention is not limited solely to fluid end 10, but encompasses any and all fluid ends within the scope of the following claims. 

1. A body for a fluid end, comprising: a metallic block having a front, back, top, bottom, and opposed sides and, also, including: a horizontal, plunger passage extending from the front to the back of said block; a horizontal, outlet passage extending from one of said opposed sides to the other, said outlet passage being positioned beneath, and being oriented at right angles to, said plunger passage; a suction passage extending vertically downward from the top of said block and intersecting said plunger passage to define a pumping chamber at the point of intersection; a discharge passage extending vertically downward from said pumping chamber to the bottom of said block, and said discharge passage being located adjacent to said outlet passage; and, a connector passage extending from said discharge passage to said outlet passage so as to place said discharge passage and outlet passage in fluid communication with one another.
 2. The body according to claim 1 wherein said suction passage has a suction valve seat deck located therein, and wherein said discharge passage has a discharge valve located therein, and wherein the top surfaces of said suction valve seat deck and said discharge valve seat deck are horizontal.
 3. The body according to claim 1 wherein said plunger passage, said suction passage, and said discharge passage are helically threaded contiguous to their respective points of intersection with the front, back, top and bottom of said block.
 4. A fluid end, comprising: a body being a metallic block having a front, back, top, bottom, and opposed sides and, also, including: a horizontal, plunger passage extending from the front to the back of said block; a horizontal, outlet passage extending from one of said opposed sides to the other, said outlet passage being positioned beneath, and being oriented at right angles to, said plunger passage; a suction passage extending vertically downward from the top of said block and intersecting said plunger passage to define a pumping chamber at the point of intersection; a discharge passage extending vertically downward from said pumping chamber to the bottom of said block, and said discharge passage being located adjacent to said outlet passage; and, a connector passage extending from said discharge passage to said outlet passage so as to place said discharge passage and outlet passage in fluid communication with one another; a reciprocating plunger assembly being located the end of said plunger passage adjacent the back of said block; a plug being located in the end of said plunger passage adjacent the front of said block; a suction valve being located in said suction passage; a discharge valve being located in said discharge passage; and, a fluid supply manifold being pivotally secured to the top of said block and being in fluid communication with said suction passage.
 5. The fluid end according to claim 4 wherein said suction passage has a suction valve seat deck located therein for retaining said suction valve, and wherein said discharge passage has a discharge valve located therein for retaining said discharge valve, and wherein the top surfaces of said suction valve seat deck and said discharge valve seat deck are horizontal.
 6. The fluid end according to claim 4 further comprising a Victaulic coupling body for releasably connecting said fluid supply manifold to said suction valve and a rubber seal positioned within said coupling body for preventing fluid leaks.
 7. The fluid end according to claim 4 wherein said plunger passage has a helically threaded portion being contiguous to the front of said block and wherein said plunger passage includes a plug deck adjacent to said helically threaded portion, and wherein said plug further includes: an access pin including: a rod portion that is sized to slide snugly past said plug deck into said plunger passage, said rod portion being provided with a concavity therein for receiving said plunger assembly when said plunger assembly is reciprocated in said plunger passage; and, a peripheral flange portion being located at the front of said rod portion and being adapted to abut said plug deck; a retaining nut being in selective contact with said access pin for holding said access pin within said plunger passage, said retaining nut including: an externally, helically threaded body being screwed into said helically threaded portion; and, a hexagonal stem projecting outwardly from said helically threaded body for permitting said retaining nut to be turned by a wrench.
 8. A fluid end, comprising: a body having a front, back, top, bottom, and opposed sides, said body being provided with a plurality of passages for the passage of fluid through said body; a reciprocating plunger assembly being located in said body for pressurizing fluid in said passages; a suction valve being located in one of said passages for maintaining a one-way flow of fluid to said plunger assembly; and, a discharge valve being located in another one of said passages for maintaining a one-way flow of fluid away from said plunger assembly, and said discharge valve being nearer to the bottom of said body than said suction valve. 